Muffle furnace



J. R. C. AUGUST.

MUFFLE FURNACE.

'APPLICATION'HLED MAY 8,1920. RENEWED JAN. 24.1922.

1,414,614. Patented n, 1922.

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J. R. 0. AUGUST;

MUFFLE FURNACE.

AAPLICATION FILED MAY 8, I920- RENEWED JAN. 24.1922. 1,414 614.

Patented May 2, 1922.

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if? 6. I r M ,1. R. C. AUGUST.

MUFFLE FURNACE. APPLICATION men MAY 8, i920. RENEWED IAN. 24.1922. 7

Patented May 2, 1922.

1 SHEETS-SHE 3- J. R. 0. AUGUST.

MUFFLE FURNACE. APPLICATION men MAY 8. I920- RENEWED JAN. 24.1922. 1,414,614.

Patented May 2, 192 2.-

1 SHEETS-SHEET 4.

J. R. C. AUGUST.

MUFFLE FURNACE. APPLICATION FILED-MAY s. 1920. RENEWED JAN. 24.1922.-

' 1,414,614, Patented May 2,1922

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MUFFLE FURNACE.

APPLICATION FILED MAY 8, 1920. RENEWED JAN. 24, 1922.

Patented May 2, 1922.

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J. R. C. AUGUST.

MUFFLE FURNACE. APPLICA'HON FILED MAY 8, 1920. RENEWED JAN. 24,1922;

Patented May 2, 1922;

7 SHEETS-SHEET 1.

6 4 v -IIH- w MW Z V v mm 1% Q I 1 M. 2 .fl 0% v y 3 .47. IX! v /V/ 2 $0 w M v 3 J'OHANNES Bonner cAnL AUGUST, on HALIFAX, ENGLAND.

MUFFLE FURNACE.

Application filed May 8, 1920, Serial No. 379,994.

To all whom it may concern.

Be it known that I, JoHANNns ROBER CARL Auous'r, subject of the King of Great Britain, residing at Halifax, Yorkshire, England, have invented certain new and useful Improvements in or Relating to Muffie Furnaces, of which the following is a specification.

This invention has reference to rotary muflie or barrel furnaces of the type in which the muflie or barrel is concentrically mounted and supported by longitudinal bearers within a rotary heating chamber or furnace so that while both revolve together spaces are left between them. These spaces form fines for the heat to pass through and be uniformly distributed about the outside of the barrel.

My improved furnace is formed by the combination of a rotary heating chamber closedat one end and having a centralaperture at the other, and a removable muffle or barrel inserted closed-end first, through the said aperture while the openv end which is closed by a detachable cover is left projecting, the space between the rotary heating chamber and the barrel being sub-divided by longitudinal bearers into a plurality of longitudinal flues for the hot gases to pass through, the bearers forming throughout their length supports for the muffle which rotates with the heating chamber. The disposition of the parts is such that the barrel can be removed from the rotary furnace chamber when required, and replaced by a new one so that cracking or breaking of the barrel will not cause a collapse of the whole furnace structure because of the ease'with which the barrel can be replaced.

The muffle furnaces with removable bar- ;"rels were manufactured and placed upon the market by me in 1913. They comprise as shown in .Figures 1 andiZ of the accompanying drawings (in which Figure 1 is a cross section and .Figure 2 a sectionalelea: vation on the line of Figure 1) a cyrotated by a worm 5 meshing lindrical metal" barrel 1 of unlined cast iron arranged to extend in a horizontal direction through a fixed'nonrotatable furnace chamber 2 in the opposite end walls 3 of which it wasmounte'd to rotate so that the barrel was surrounded by heat. This barrel was mounted on external carrying rollers 4:, and with a worm wheel 6 fixed to the barrel. The barrel 1 Renewed January 24, 1922. .Seri'aI No. 531,511..

was closed at one end 7, while'the other end was provided with a removable gas tight closure 8 to enable articles to beinserted into or removed from the barrel. I The temperature in the barrels 1 is very high and destructive to the cast iron or steel of which they are made, and as they cost anything from 18 to 30 each, and very seldom last more than ten days and sometimes very much less, the waste of material and expense involved is very unsatisfactory.

- It will be noted that there is a very considerable span between the supports 3 in which the barrel 1 is mounted and as the barrel weighs about 15 cwts. or more, and the barrel at the high tem erature at which it works.(800 or 900 5 becomes quite soft, so that sagging of the barrel is liable to occur, it will beunderstood that the conditions under which the barrel works are very severe especially when it is loaded with 3 or 4 cwts. of material,-the result being that the barrel will not for long withstand the rotary drive which in course of time twists and breaks it long before the metal is worn out.

The improvements which characterize the present invention will be understood from the following description reference being had to the accompanying drawings in Figure 2 1s a sectional elevation thereof.

on the line A-B of Figure 1.

Figure 3 is a longitudinal section of a solid fuel fired furnace embodying my improvements,

Figure 4 is a cross section thereof through.

the. mufiie. Figure 5 is a vertical sectionthrough the firebox, Figure 6 is a longitudinal section showing my improvements applied, toa gaseous or liquid fuel fired furnace. y Figure 7 is a crosssection thereof with the barrel removed. 1 4

Figure 8 is a longitudinal section of a solid fuel fired furnace similar to that shown in Figure 3, but provided with means for automatically feeding the muflie at one end. Referring first to Figures 3, 4 and 5, the rotary heating chamber or furnace com prises a cylindrical metal casing 20, lined inside with fire clay slabs 21 and extends in a horizontal or slightly inclined direction, and the barrelor muffle 22 is supported in side this casing by longitudinal firebrick beaiers 33, which serve to support the barrel concentrically inside the casing 20 and divide up the space between the barrel and the outer furnace chan'iber into a number offiues 23. w At one end the rotary cylinder casing 20 has a eircular concentric aperture 25, through which is passedthe barrel 22; This barrel which may"be made of fire-clay is closed at thelinn'er'end' 26, while the outer 7 'nut's-and'set'pins to the flanged outer end of end which be enlarged a little as shown extends: a little beyond the end of the cylindrica-l casing-"20 and is provided-with a re mo'vablegas tight cover or closure 27. This cover may consist of a plate 27 secured by the barrel 22, and may carry on its inner side by means of rods, an inner plate or diaphragin 27* which abuts against the shoulder'at'the junction between the barrel 1 proper andits enlarged end. By the removalof this'cover, the articles to be sub jected to-"heat treatment can-be readily iii- TFOClHCBCl' aHd afterwards withdrawn. 7 The cylindrical casing-20, 21 together with the bearers and the barrel 22, is rotated by aworm 2'8 ineshing with a worm wheel "29-'on the external circumference of the said casing-or rotary furnace '20 The disposition of the parts enables theibarrel 22 to be Wltl1' drawn at any timewhen worn out or burnt through and replaced by new one without disturbing the outer casing or the bearers 3'3.

The outer circuinference'of the said casing is bondedwith metallic bands 30 some of 7 these forming the moving trackways for the carrying rollers 31.".In the arrangement shown in these figures, the hot gases forheating the barrel 22 are generated'by the burning of solidfuel in a fire box 32. At

least two of the flues 23 are left open atthe end where the heat is admitted as shown by the fllll'llIlQS in Figure 5 so that the gases from the'burniiig'fuel in the fire box 32 may enter into them, when an open endcomes opposite a port 345- in the wall of the perpendicular fine 36, or escape therefrom to the chimney24 when an'open end comes opposite another port35; The rotary heating cham- V benrotates against a 'fixed'head in which are formed the's-aid ports 34:, 35 such ports being located at the same radius from the longitudinal axisof-th'e'rota'ry chamber as the said fines, so that when the apparatus is rotated the hot gases will at intervals enter the fines, and after they have made their circuit, escape from the fines when the open end of such flues come intocoi ncidence with the port 35. 'If desired theremay of course be'more than one heat inlet port 343- and more than one-outlet port 35: The means for enabling a backwards and forwards horiaway a little at alternate ends in such manner as to enable the hot gases after passing,

forwardly through one flue 23 to pass into and return through the nextv one,- -then forwardly through the succeeding fiue and-so on alternately until they finally: escape through the other open ended flue when it comes opposite the'port 35that leads to "the chimney 24. I The fire box 32- is located in a suitableposition relative to the'rotary cas ing or furnace, and'the roductSofcOInbus tion pass upwards through the perpendicular flue36 which is closed about the centreline' of'the said rotary casing by'a fire brick slab '87, while abovethis slab, the flue extends upwards to the chimney'Qt. These lines are located at the'rear end of the rotary casing or furnace, that is at the opposite end t'o'the removable-gas tight cover or closure of thebarrel, and the said rear end abuts and rotates against the wall of the said perpendicular fine.

The wall ofthis flue below the'slab has a port hole 34 alreadymentioned" through which the combustion'gases enter a longitudinal flue 23 outsidet he barrelfQIQ, while the wall of the perpendicular flue abovethe slab 37 has another port hole '35 in it, by which the combustion products escape'after following a circuitous cou rse forwards-and backwards longitudinally of the barrel22, these port holes being so located say??? coincideswith one ofthe port holes la,

the open end 'of'the other open endedhue' roincideswith'the otherporthlole 35. It will be understood therefore that a-streain of hot gases will passbackwards and forwards of" the barrel on-theoutside thereof, between it:

that when the open end of one of theseflues and the outer chamber and throughout its" length, so that the heat is uniforinl'y dis ti'ibuted' about the barrel which is thus not If desired this form of furnace can be heated by liquid fuel instead ofby the hot gases being generated by the burning of-solid fuel.

An-arr 'angemei'it of furnace heated 'by the" burning ofjliquidor gaseous fuel or powde'r'ed fUGLCOHJPIISQSa 'rotaryfurnac'e chainheated more atone end thaii'at the othereiid; f

her 20 extending'somewhat beyond; the bar-" rel QQat-the'end opposite'to that where the" removable gas tight cover or closure 27 is located, and the interior at' theend-QO is made of conoidal shape while the correspond iiig end of the barrel 22'which is closed is made of similar shapere'feren ce being had to Figures (i -and 7. The barrel is supportech inside 1 the furnace chamber by longitudinal fire brick bearers 40 spaced'apartto form fines, and the niuflleisheated by gas and' 'air' admitte'd by a burner- 41' at the c'onoidal' end" the furnace chamber 20, which points toemma 3 wards the conoidal endof the barrel 20, the

inside of the barrel at that end being'packed with 'asbe'stos or other suitable material" if desired. The hot combustion products im-- pacting' against the conoidal-end'o-f the barrel 20 pass along the fines formed by the bearers 40 from one endlto the 'o'tlier and where they are discharged through'radial openings 42 in the furnace cha'mb'er 20 into an annular stationary chamber 43 outside the rotating furnace chamber from whence they escape to the chimney 44; If desired, the rotary furnace 21 with its inside barrel 22 may be provided with a feeding chute 45 at the closed end, as shown in Figure 8, delivering into the muffle at the ,axis of rotation, and with means for delivering the articles removed through the cover 27 at the other end into a cooling medium contained in the receptacle 46, as, for example, oil or water, and a spiral device 47 may be provided inside the barrel 22 to produce a screw effect. In this case the rotary furnace 21 with its barrel 22, may extend in a slightly inclined direction and as the articles to be subjected to heat treatment are fed into the barrel at one end through the chute 45 from the hopper 48, they are caused to continually move towards the delivery end by the action of the spiral 47 and be finally delivered thereto through the aperture 49. In this particular figure the barrel or muffle 22 is supported inside an inner heating chamber 21 by fire brick bearers 38*, so as to divide up the space into a number of flues,and this inner chamber 21 is supported inside the main outer heating chamber by a number of similar fire brick-bearers 33, the two sets of fiues being interconnected as shown. Any heat escaping through the aperture 49 is more than compensated for by the supplemental-y set of fiues between the barrel 22 and the inner furnace. The remaining reference numerals in this Figure 8 refer to like parts in Figures 3 and 4.

I declare that what I claim is 1. A rotary furnace of the rotary barrel type, formed by the combination of a rotary heating chamber closed at one end, and having a central aperture at the other, and a removable muffle or barrel'inserted closed end first, through the said aperture while the open end which is closed by a detachable cover is left projecting, the space between the rotary heating chamber and the barrel being subdivided by longitudinal bearers into a plurality of longitudinal flues for the hot gases to pass through. the bearers forming throughout their length supports for the mufile which rotates with the heating chamber. V

2. A rotary furnace of the rotary barrel type, comprising in combination a rotary heating chamber, a removable muffle inserted closed end ,fi'rst into' the-said chamber, loninto fines, such bearers" bein'g"cut"awayat 'alternateends'in such manner as-to enable the hot gases after passing forx'vard-ly into and return then forwardly through "one this to pass through the next' one; through the succeeding flueand so cn 'a1ter-' nately, so, as to provide adequate top and bottom heat. i

3. A rotary furnace of the rotary barrel type, comprising in combination a rotary heating chamber, a removable muflie mounted and supported inside the chamber by bearers and in which at least two of the longitudinal Hues inside the rotary heating chamber are left open at the end where the'heat is admitted, and the rotary heating chamber rotates against a fixed head provided with ports located at the same radius from the longitudinal axis of the rotary chamber as the said flues, at least one of these ports being an intake for the heating gases and another a discharge o-pening,through which the hot gases escape to the chimney, so thatwhen the apparatus is rotated the hot gases will at intervals enter'the flues, and after they have made their circuit, escape from the fines when'the open end of such fines come into coincidence with'the port.

4. A rotary chamber of the rotary barrel type, comprising in combination a rotary heating chamber, a removable muffle mounted and supported inside the chamber by bearers a perpendicular flue passes upwards from the fire box against-onewall of which flue the rotary heating chamber with its internal mufl'le and bearers rotate, the said perpendicular flue being closed about the centre line'of the said rotary heating chamber by a fire brick slab above which the flue heating chamber, a removable muffle mounted and supported inside the chamber by bearers, the said chamber extending somewhat beyond the barrel at the end opposite to where the removable gas tight cover is located and the interior of the said end is made ofconoi dal shape while the corre spending end of the barrelwhich is closed and spaced away from the heating chamber is made of similar shape, and in which the muflie is heated by fuel gas admitted by a central burner at the co-noidal'end of the rotary chamber, so asto direct the heatagainst the said conoidal end and cause it to pass "along the longitudinal flues between the bearers all round the barrel.

6. A; rotary hirnaceofitherotary barrel tion produetsere discharged through the 10 type, comprising in combination a rotary radial openings. v v V V V v heating chamber, a removablemufllemouht: In Witmese. whereof, I have hereuntoed and supported inside the chamber by signed my name this 19th dayrof Ap1' i151920, V hearers, a central burner for fuel gas, at one in the presence of two subscribing Witnesses.

end of therotary ehzunhef, radial openings QHA UYE ROBERTVCARFAUGUST- inthe chamber atthe other end thereof and vWitnesses: V r I an annular fixed chamber utside the 110 AUGUSTUS EFYINVGBAMQ tiny chamber int-o" which the; hot combusv .EDQ.;B. NIeH Ls. 

